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<head>
  <meta charset="UTF-8">
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  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <canvas id="circle" width="600" height="600" style="border: 1px solid orange;"></canvas>
  <script>
    const canvas = document.querySelector('#circle')
    const ctx = canvas.getContext('2d')

    ctx.lineWidth = 15
    ctx.strokeStyle = 'purple'

    ctx.beginPath()
    ctx.arc(300, 300, 200, 0, Math.PI * 2, false)
    ctx.stroke()

    ctx.beginPath()
    ctx.arc(300, 200, 100, -Math.PI / 2, Math.PI / 2, true)
    ctx.strokeStyle = 'green'
    ctx.stroke()

    ctx.beginPath()
    ctx.arc(300, 400, 100, -Math.PI / 2, Math.PI / 2, false)
    ctx.strokeStyle = 'red'
    ctx.stroke()

    ctx.beginPath()
    ctx.arc(300, 200, 50, 0, Math.PI * 2, false)
    ctx.fillStyle = 'red'
    ctx.fill()

    ctx.beginPath()
    ctx.arc(300, 400, 50, 0, Math.PI * 2, false)
    ctx.fillStyle = 'green'
    ctx.fill()
  </script>
</body>

</html>